Motor vehicle cooling systems for cooling engine coolant, refrigerant vapor and transmission oil are known in which either an oil cooler or a refrigerant condenser unit are located upstream of the cooling air inlet side of the radiator for removing heat from the coolant system for an liquid cooled engine. Examples of such systems are set forth in U.S. Pat. Nos. 3,479,834 and 4,138,857.
Such location exposes the tube passes of the refrigerant condenser and/or oil cooler to ram air flow as the vehicle is driven in a forward direction. Furthermore, such location causes the engine fan to draw cooling air across the condenser while the vehicle is stopped or slow moving and the engine is idling. As a consequence the condenser is operative to condense refrigerant gas to a liquid which is then directed across an expansion valve for controlling the flow of refrigerant into a refrigerant evaporator. A circulating fan draws air flow across the evaporator for cooling the interior or passenger compartment of a motor vehicle in a known manner. Likewise a continual flow of cooling air is directed across the oil cooler.
While the forward or upstream location of the refrigerant condenser is a favorable location for providing continual air flow across the tube passes of the condenser and/or oil cooler, such refrigerant condensers and oil coolers have separate air centers and the radiator has separate air centers which can cause undesirable contraction, expansion, contraction cycles in the inlet airstream for cooling the separate components of combination radiator and condenser apparatus for motor vehicles. Such pressure cycles in the inlet airstream result in an increased pressure drop that will reduce the cooling effectiveness of the inlet airstream of the vehicle.
In the past such reduction in cooling effectiveness has been compensated by providing a slightly oversized frontal area in the radiator or the condenser could be located laterally of he radiator so as not to retard air flow therethrough. An example of a laterally offset condenser is set forth in U.S. Pat. No. 3,337,596.
Present vehicle design constraints have reduced the available space for such oversized radiators or for such offset condenser configurations.
Additionally, in future automobile air conditioning systems high cost alternative refrigerants are being proposed. In order to minimize the amount of such refrigerant required to effectively cool a vehicle engine compartment it will desirable to reduce the size of the condenser to reduce the total volume of refrigerant in the system but without reducing the cooling capacity of the condenser.
Furthermore, present day radiators often include a plastic coolant tank which are joined to metal headers and support frames in which are located tube passes and air centers for flowing the inlet air stream of a vehicle for removing heat from coolant passing through the tube passes. Header and tube construction are used in the manufacture of refrigerant condensers having high pressure refrigerant flowing through tube passes connected to air centers having the inlet air stream of the vehicle directed therethrough for cooling the refrigerant vapor for condensation to high pressure liquid refrigerant. Partitions are provided in the header tank condenser to provide a serpentine fluid flow path through the condenser. Both the radiator and the condenser are separately manufactured and separately mounted either laterally of one and other or with the condenser located upstream of the radiator. Such arrangements increase the space and weight requirements of the combination apparatus. One approach to weight containment has been to strengthen the header portion of either a radiator or a condenser by providing a dome in the header to reinforce tube openings therein. Another approach has been to provide a condenser with a tube header with spaced slots therein to receive the ends of parallel tube passes and partitions for forming a serpentine condenser pattern. Neither of the proposals suggest a unitary construction which combines both a radiator for coolant and a condenser for high pressure refrigerant.
In prior combination radiator and condenser apparatus no solution has been proposed which will enable a condenser and a radiator to be located in limited space confines of a motor vehicle without adversely affecting the flow of coolant air flow across one or both of the separate condenser and radiator units.
In order to meet space and weight design constraints and inlet airstream flow patterns in a motor vehicle an object of the present invention is to provide a combined radiator and condenser apparatus in which fewer parts are used than in separately fabricated radiator and condenser units. A further object is to provide such a combination apparatus in which thin gage aluminum centers are common for both the radiator and the condenser and each of the radiator and condenser units share a common tank member and common header plates. A feature of the invention is to improve the packaging of combined radiator and condenser apparatus by eliminating an expansion gap between the condenser and the radiator such that the radiator and condenser can be mounted to the vehicle as one unit rather than as two separate units thereby to eliminate the weight of one mounting unit. An extruded tank has an integral internal partition which separates the extruded tank into a coolant chamber and a high pressure refrigerant chamber and wherein the tube passes of both the radiator and the condenser are bonded to an integral wall of the extruded tank at tube access slots therein and wherein the tubes have the same air centers for defining a single air flow path through both the radiator and the condenser which will not increase the pressure drop across the radiator and condenser as the inlet airstream of a motor vehicle is directed thereacross. The extruded radiator configuration provides greater strength and enables more robust designs to be configured than in the case of designs including plastic tank with rubber gasket seal sets as found in present day radiator assemblies.